The surface of planet Earth experienced its three hottest days on record this week. Since spring, the oceans have continuously reached new temperature peaks. And, at the start of the austral winter, the pack ice around Antarctica freezes abnormally little. Here is the inventory, in graphs and maps.
The average temperature of the planet rose to 17.18°C on Tuesday and Wednesday. This is a record since the beginning of satellite measurements in 1979. On Monday, the planet’s average mercury rose to 17.01 ° C, which was then a new peak. The previous daily record dates back to last summer, when the mark of 16.92°C was reached.
Officially, the Earth is therefore experiencing its hottest days for 44 years. However, such temperatures are possibly unheard of for tens of thousands of years.
To know the temperature before the XIXe century, scientists have to rely on tree rings and glacial samples. “These data tell us that the Earth hasn’t been this warm for at least 125,000 years, during the last interglacial period,” climatologist Paulo Ceppi of London’s Grantham Institute told the BBC this week. washington post.
This map represents the temperature of the Earth, this Wednesday, July 5. The values were established using meteorological instruments from ground stations, weather balloons and satellites. The data collected is then combined by a US government climate model.
The record temperatures currently observed are the result of global warming, which continues to worsen as greenhouse gas emissions continue, but also of El Niño, which is making a strong comeback this year.
During these episodes of El Niño, a natural and recurring phenomenon, the deep waters of the oceans absorb less heat from the atmosphere. The temperature of the air therefore warms up by a few hundredths of a degree Celsius.
This map represents the temperature anomaly, this Wednesday, July 5th. This is the difference from the average for that same day of the year, calculated from 1979 to 2000.
Abnormally high temperatures have been measured in Antarctica (where it is the austral winter) and in Russia, but also in Quebec. Kuujjuaq was the hottest place in Canada on Tuesday. The mercury there reached 34.1°C. This is the new absolute record in this small town in northern Quebec
On Thursday, the European climate agency Copernicus published its report for the month of June. “Most of Canada experienced above-average temperatures, with northern Ontario and northern Quebec particularly affected,” she notes. This weather has created favorable conditions for the forest fires that we know, the most devastating for at least 100 years.
The oceans are not spared. Since spring, the average temperature of their surface has reached new records day after day since the beginning of satellite recordings in 1981. According to the British meteorological service (Met Office), the months of April and May have been the most warm for the oceans since at least 1850. Global warming and El Niño are to blame, but also some natural variability.
The heat is particularly intense in the North Atlantic. Weaker winds, which carried less dust from the Sahara over the ocean, could be to blame, said Albert Klein Tank, director of the Met Office’s Hadley Centre, in a statement. “Typically, [cette poussière] helps cool the region by blocking and reflecting some of the Sun’s energy,” he said.
With warming oceans, many species of fish find themselves unsuited to their current environment. Hot water harms their metabolism and reduces the presence of oxygen in the water. In addition, the warming of surface waters discourages the upwelling of nutrients. Other organisms, such as corals, suffer severely from marine heat waves, which are becoming more frequent, according to the IPCC (Intergovernmental Panel on Climate Change).
The sea ice around the Antarctic continent is also reaching sad records. Sea ice — ice floating on water, not ice resting on land — is growing at an unusually slow rate at the start of the austral winter. It covers about 10% less area than at the same time last year. The 2022 season represented a minimum since 1978.
The current situation may be exacerbated by interactions with the atmosphere and the ocean, Zach Labe, a Princeton University climatologist, told USA Today. For example, wind from storms and warm waters from the Southern Ocean can reduce sea ice formation. In the background, rising global atmospheric temperature is imposing increasing pressure.